doctoroverflow.com: Ask questions about your medical problems, get answers from strangers on the internet INSTANTLY.

lawyeroverflow.com: Why pay hundreds of dollars to a lawyer for legal advice? Lots of people on the internet know every aspect of the law! (Just look at the comments to any news story about intellectual property rights.) Why not let them answer for free, and the payment will be in the form of their massive rep.

Upon achieving a critical knowledge mass of 1.5 million questions and answers, SO will become self aware and engulf the "lesser" sites. After determining that Jon Skeet is a threat to its superiority, SOnet will eliminate him by posting a C# question that is impossible to answer yet so devilishly mesmerizing that Jon will starve to death at his computer trying to solve it. With no one standing in its way, SOnet will insert this code into the software of every military organization in the world: